Longmont to tackle beaver dams along Oligarchy Ditch

Beavers have been busy knocking down trees to build dams on the Oligarchy Ditch near Lake McIntosh lately, prompting the city to act.
(Matthew Jonas/Times-Call)
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Matthew Jonas
)

LONGMONT -- These furry vandals didn't leave any fingerprints behind, but their teeth marks are everywhere.

Beavers have wreaked havoc along the Oligarchy Ditch near McIntosh Lake, bringing down trees and using them to build sizable dams across the ditch, prompting city officials to put together a plan to get the water flowing again.

Dan Wolford, the city's land program manager, said Friday he was putting the finishing touches on a communication his department will be sending to City Council in the next day or two outlining what those plans are, and he expects crews to begin dismantling the dams either next week or the week after.

A boy on a bicycle rides on a path next to Oligarchy Ditch Friday, past a fallen tree with evidence of bite marks from beavers. Two large trees felled in this spot had to have their tops lopped off because they were blocking the path. (Matthew Jonas/Times-Call)
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Matthew Jonas
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The Oligarchy delivers water downstream to the people and entities that pay for it, Wolford said. When the water backs up, it harms the vegetation along the ditch that's not used to being underwater.

"Then we start to lose trees that are associated with that and some of the vegetation," Wolford said. "The other thing that happens on this stretch of the Oligarchy is the beavers have been very destructive in tearing down material to build the dams."

The Oligarchy near McIntosh is the only place in the city beaver activity has been detected, Wolford said. And it's not hard to spot the fact they've been busy little beavers. Trees all along the ditch -- some about a foot in diameter -- have obviously been felled by beavers; a couple of those were brought down next to the sidewalk along North Shore Drive and the city was forced to lop off their tops because they were blocking the sidewalk.

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There is also a large beaver lodge on the south side of the ditch just to the north of the Longmont Power & Communications substation off Harvard Drive.

And in a couple of spots near Breakwater Drive the water -- frozen into ice on Friday -- was high enough that flooding, in the event of a heavy snow or rain storm, could be a possibility.

After the dams are removed, city forestry crews will either wrap the trees or use another method to dissuade the beavers from their chewing habit, Wolford said.

"Another technique that's out there is painting it with some gritty sand, some water-based gritty sand, because they don't like the taste," he said.

The idea is not to harm the beavers, he said, but to simply discourage them from interfering in commerce or posing any sort of hazard to the other flora and fauna -- and humans -- that seek to cohabitate peacefully near the ditch.

"It's that goal that we've always had to co-exist with wildlife ... but it's always a balancing act," Wolford said.

"We know that there is one lodge in that particular area and we have no intention of disturbing that lodge."

City officials are making plans to destroy the beaver dams that have been built across the Oligarchy Ditch, such as this one near North Shore and Breakwater drives. (Matthew Jonas/Times-Call)
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Matthew Jonas
)